I guess I asked the question from a wrong perspective. Due to dependent origination, when the conditions for ignorance ceases to exist, ignorance ceases to exist. In the same way that life has no beginning, ignorance can’t begin from “nothing”. This is why the rebirth process has no discernible beginning (which is a logical concept but not very intuitive at first). When I asked the question I was thinking about citta as being separate phenomenas.
Lal, would it be correct to say there is no discernible ending to ignorance in the world? There must be an infinite amount of lifestreams. If there was a specific, limited amount of lifestreams, then everyone would already have reached nibbana, since life had no beginning and sammāsambuddhas appear periodically.